In general, a more compact and efficient rotating electric machine can be obtained by using magnets with stronger magnetic force. However, if the magnetic force of magnets is too strong, the magnets may swiftly be drawn to a rotor main body of a magnetic substance by attraction, hit thereupon, and crack during assembly of the magnets to a rotor. Operation postures become unstable because the magnets must be assembled on the outer circumference of the disk-shaped rotor. A magnet to be assembled will be immediately next to another magnet of an opposite polarity that has been previously assembled. Magnet assembling work must be carried out against the strong attraction force generated between the two magnets, which lowers the workability of assembling the rotor.
The rotating electric machine once assembled includes magnets and a stator disposed opposed to each other at a very small gap distance therebetween. More specifically, the core of the stator is always attracted by the magnetic force of the magnets. Therefore, when implementing the repair and maintenance of the rotating electric machine, the rotor and the stator must be disassembled and reassembled against the strong magnetic attraction force, which lowers the workability, prolongs the work period, and hence increases work costs. As the size of the rotating electric machine increases, the sizes of the rotor and the stator increase, and the number and size of the magnets increase. Therefore, the disadvantage associated with the assembling workability becomes more apparent.
In connection with the disadvantage, PTL 1 suggests a structure in which the outer circumferential part of the rotor is provided discretely as a rotor core, and magnets are assembled to the core and fastened to the rotor main body. In this way, the work of assembling the magnets can be carried out to a rotor core which is smaller than the rotor main body. Therefore, the assembling workability of the rotor can be improved. The rotor core can be removed from the rotor after the completion of the assembling, which facilitates repair works.